循环队列是一种具有固定大小的队列，当队列满时，新元素将会覆盖最旧的元素。下面是一个简单的C++循环队列的应用实例，实现了一个基本的生产者-消费者模型。
#include <iostream>using namespace std;#define SIZE 5class CircularQueue {private: int arr[SIZE]; int front, rear;public: CircularQueue() { front = -1; rear = -1; } void enqueue(int value) { if ((front == 0 && rear == SIZE - 1) || (rear == (front - 1) % (SIZE - 1))) { cout << "Queue is full" << endl; } else if (front == -1) { front = rear = 0; arr[rear] = value; } else if (rear == SIZE - 1 && front != 0) { rear = 0; arr[rear] = value; } else { rear++; arr[rear] = value; } } int dequeue() { if (front == -1) { cout << "Queue is empty" << endl; return -1; } int value = arr[front]; arr[front] = -1; if (front == rear) { front = rear = -1; } else if (front == SIZE - 1) { front = 0; } else { front++; } return value; } void displayQueue() { if (front == -1) { cout << "Queue is empty" << endl; return; } cout << "Elements in the circular queue are:" << endl; if (rear >= front) { for (int i = front; i <= rear; i++) { cout << arr[i] << " "; } } else { for (int i = front; i < SIZE; i++) { cout << arr[i] << " "; } for (int i = 0; i <= rear; i++) { cout << arr[i] << " "; } } cout << endl; }};int main() { CircularQueue q; q.enqueue(1); q.enqueue(2); q.enqueue(3); q.enqueue(4); q.enqueue(5); q.displayQueue(); cout << "Dequeued element: " << q.dequeue() << endl; q.enqueue(6); q.displayQueue(); return 0;}在这个示例中，我们定义了一个CircularQueue类，实现了循环队列的基本功能，包括入队、出队和显示队列元素。在main函数中，我们演示了如何使用循环队列模拟生产者-消费者模型。首先入队5个元素，然后出队一个元素，最后再入队一个元素。最终打印出队列中的元素。
